I just thought I would update this with a quicker way of repairing the snaps toolbar - I think this happens if you use hard copy file versions of Max's settings into later versions, but who knows really.
You can go into "Customize User Interface", and the "Toolbars" tab.
Click on "Save..." button twice and save two versions of the toolbar settings (they have CUIX file extensions), and then find the file you just saved. KEEP ONE AS BACKUP IF THIS DOESN'T WORK FOR YOU.
Open up the file in notepad and search for:
Window objectName="Snaps" name="Snaps"
Select everything from:
<Window objectName="Snaps" name="Snaps" type="T" cType="1" toolbarRows="1">
down to the next line that says:
</Window>
Select everything below and paste this over that, save the file as the newtoolbar.CUIX, go back into Max, and then load this updated file in the Customize User Interface menu (as above) and it should update your buttons correctly.
<Window objectName="Snaps" name="Snaps" type="T" cType="1" toolbarRows="1">
<Items>
<Item typeID="2" type="CTB_MACROBUTTON" width="0" height="0" controlID="0" macroTypeID="4" macroType="MB_TYPE_ACTION_CUSTOM" actionTableID="1259304063" imageID="0" imageName="Snap_Points" actionID="40000" tip="Snap To Grid Points Toggle" label="" />
<Item typeID="2" type="CTB_MACROBUTTON" width="0" height="0" controlID="0" macroTypeID="4" macroType="MB_TYPE_ACTION_CUSTOM" actionTableID="1259304063" imageID="1" imageName="Snap_Points" actionID="40001" tip="Snap To Pivot Toggle" label="" />
<Item typeID="2" type="CTB_MACROBUTTON" width="0" height="0" controlID="0" macroTypeID="4" macroType="MB_TYPE_ACTION_CUSTOM" actionTableID="1259304063" imageID="4" imageName="Snap_Points" actionID="40006" tip="Snap To Face Toggle" label="" />
<Item typeID="2" type="CTB_MACROBUTTON" width="0" height="0" controlID="0" macroTypeID="4" macroType="MB_TYPE_ACTION_CUSTOM" actionTableID="1259304063" imageID="3" imageName="Snap_Points" actionID="40002" tip="Snap To Vertex Toggle" label="" />
<Item typeID="2" type="CTB_MACROBUTTON" width="0" height="0" controlID="0" macroTypeID="4" macroType="MB_TYPE_ACTION_CUSTOM" actionTableID="1259304063" imageID="2" imageName="Snap_Points" actionID="40005" tip="Snap To Edge/Segment Toggle" label="" />
<Item typeID="2" type="CTB_MACROBUTTON" width="0" height="0" controlID="0" macroTypeID="4" macroType="MB_TYPE_ACTION_CUSTOM" actionTableID="1259304063" imageID="5" imageName="Snap_Points" actionID="40004" tip="Snap To Midpoint Toggle" label="" />
<Item typeID="3" type="CTB_SEPARATOR" width="6" height="16" orientation="31" visible="1" />
<Item typeID="2" type="CTB_MACROBUTTON" width="0" height="0" controlID="0" macroTypeID="3" macroType="MB_TYPE_ACTION" actionTableID="0" imageID="-1" imageName="" actionID="40905" tip="Snaps To Frozen Objects Toggle" label="Snaps To Frozen Objects Toggle" />
<Item typeID="2" type="CTB_MACROBUTTON" width="0" height="0" controlID="0" macroTypeID="3" macroType="MB_TYPE_ACTION" actionTableID="0" imageID="-1" imageName="" actionID="40904" tip="Enable Axis Constraints in Snaps Toggle" label="Enable Axis Constraints in Snaps Toggle" />
</Items>
</Window>